Method for transmitting data and a device having data transmission capabilities

ABSTRACT

A method for transmitting data, the method includes scanning at least a first memory unit to retrieve data segments associated with multiple TDM channels, in response to a definition of multiple TDM time frames, each TDM time frame includes multiple time slots; sending the retrieved data segments to an array of line shifters; multiplexing data segments provided from the array of line shifters, in response to the definition, such as to provide in a parallel manner multiple data segments to multiple TDM lines; and transmitting a group of time division multiples data frames over a group of TDM lines.

FIELD OF THE INVENTION

The invention relates to devices and methods for transmitting data,especially over Time Division Multiplex (TDM) lines.

BACKGROUND OF THE INVENTION

In today's telecommunications, digital networks transport large amountsof information. Network services can be, for example, traditional voicephone, facsimile, television, audio and video broadcast, and informationtransfer.

With the increasing need of information exchange in the global society,the capacity of existing and future networks must be used efficiently.Multiplexers switch different network services to a single network insuch a way that every service is fully maintained and does not disturbother services.

In the near future communication controllers and their components willhave to be cheaper but also will have to cope with a dramatic incrementin the number of supported data sources, higher communication rates andto efficiently adapt to dynamic communication scenarios.

There is a growing need to support more communication channels and toperform the multiplexing operation in an efficient manner, withoutcomplex and area-consuming components.

Yet there is a growing need to design communication controllers andcommunication controller components (including serial interfaces) in amodular manner, which will facilitate a re-use of many portions ofdesigned components.

SUMMARY OF THE PRESENT INVENTION

A device having transmission capabilities and method for transmittingdata, as described in the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description taken in conjunction with thedrawings in which:

FIG. 1 illustrates a multi-channel communication controller according toan embodiment of the invention;

FIG. 2 illustrates a portion of a device according to an embodiment ofthe invention;

FIG. 3 illustrates a line shifter and an empty detection unit accordingto an embodiment of the invention;

FIG. 4 illustrates a data interleaver and its environment according toanother embodiment of the invention;

FIG. 5 illustrates a data DE-interleaver and its environment accordingto an embodiment of the invention;

FIG. 6 illustrates a serial interface according to another embodiment ofthe invention;

FIG. 7 illustrates a device according to an embodiment of the invention;

FIG. 8 illustrates a method for transmitting data according to anembodiment of the invention;

FIG. 9 illustrates a method for transmitting data according to anembodiment of the invention;

FIG. 10 illustrates a method for de-interleaving data, according to anembodiment of the invention; and

FIG. 11 illustrates a flow chart of a method according to an embodimentof the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention illustrated in the accompanyingdrawings provide methods and devices that transmit sequences of datasegments and perform data retrieval on a TDM frame basis or on a TDMframe portion basis.

Data segments associated with multiple TDM channels are retrieved andprovided to an array of data buffers and line shifters. The lineshifters are connected to multiplexers that select which data to send asan output to a certain TDM line. Conveniently, counters are used forretrieving data segments, providing the data segments to the linebuffers and scanning selected inputs of the multiplexers.

Conveniently, the TDM frame basis data retrieval and data processingease the timing constraints imposed on a TDM channel based dataretrieval. Conveniently, the same clock signal is provided to variousdata retrieval, line shifters and data buffers thus simplifying thesynchronization between the various components.

Conveniently, the number of supported TDM channels can dramaticallychange without altering the structure of the device and especially of amulti-channel communication controller that controls the data retrievaland data processing.

It is noted that the term data includes text, graphics, video, audio, orany other information represented in a computer readable format.

FIG. 1 illustrates a communication controller 19 according to anembodiment of the invention.

Communication controller 19 is included in device 10. Device 10 caninclude one or more integrated circuits.

Communication controller 19 includes: (i) Multiple time divisionmultiplex (TDM) transmitters (collectively denoted 20) adapted totransmit a group of data frames over a group of TDM lines 9-1-9-K(collectively denoted 9). (ii) Controller 30, adapted to define orreceive a definition of multiple TDM time frames, whereas each TDM timeframe includes multiple time slots. (iii) A group 50′ of line shifters.(iv) Data retriever 40, adapted to scan at least a first memory unit(such as memory unit 11 connected to DMA controller 12) to retrieve datasegments associated with multiple TDM channels, in response to thedefined TDM time frames and to send the retrieved data segments to anarray 50 of line shifters. A data segment is an amount of data that canbe set during the smallest TDM time slot. It defines the granularity ofthe TDM frame. The group 50′ of line shifters can include the array 50of line shifters and optionally additional line shifters. Array 50includes active lines shifters—line shifters that participate in acurrent transmission session. The additional line shifters (alsoreferred to as additional line shifters) can be activated during othercommunication sessions. For example, referring to FIG. 1 the array 50 ofline shifters include line shifters 50-1 till 50-R while the additionalline shifters include additional line shifter 50-(R+1) till 50-(R+D).All line shifters (including the additional line shifters) are includedwithin group 50′. (v) Multiple multiplexers 60 adapted to multiplex datasegments provided from the array of line shifters, in response to thedefinition, such as to provide in a parallel manner multiple datasegments to multiple TDM transmitters 20. The multiple multiplexersinclude multiple active multiplexers (such as multiplexers 60-1 till60-K) and optionally additional multiplexers such as multiplexer60-(K+1). (vi) Multiple data buffers collectively denoted 90. Forexample, referring to FIG. 1 there are R active data buffers (databuffers 90-1 till 90-R) and D additional data buffers—90-(R+1) till90-(R+D). (vii) At least one clock signal provider 70 that is adapted toprovide a first clock signal (system clock signal) to the array 50 ofline shifters and to the multiple multiplexers 60 and to provide atleast one other clock signal (TC clock signal) to the multiple TDMtransmitters 20. (viii) Multiple multiplexer scanners 62 adapted to scanselected inputs of the multiple multiplexers 60, and (ix) data retrievalcounter 32 that is synchronized to the multiple multiplexer scanners 62.

It is noted that in some cases all the line shifters, the data buffersand/or multiplexers are activated.

Conveniently, communication controller 19 is adapted to receive ordefine a number of TDM lines that form the group of TDM lines. The TDMlines participate in the current transmission session and can also bereferred to as active TDM lines. This definition can be provided by auser, can be associated with a certain task or application executed bydevice 10 and the like.

Conveniently, communication controller 19 is adapted to define a numberof line shifters that form the array 50 of line shifters in response tothe number of TDM lines. Conveniently, the group 50′ of line shiftersincludes G line shifters and there are K active TDM lines. Accordingly,the array 50 of line shifters will include R=n*K line shifters, whereinn is a positive integer, n*K is not bigger than G while (n+1)*K isbigger than G.

It is noted that each line shifter (generally referred to as 50-r) ispreceded by a data buffer (generally referred to as 90-r). The inventorsused data buffers that were able to store two data segments at once. Twodata segments can be transmitted during two TDM time slots.

Conveniently, data retriever 40 is adapted to scan the at least firstmemory unit at a scanning interval that is responsive to the number ofTDM lines. The scanning interval is usually equal to the number ofactive TDM lines multiplied by a positive integer. Thus, if there areseven active TDM lines and there are thirty-two available line shiftersthen only twenty eight line shifters are active and the scanninginterval can be twenty eight. When using two data segment long lineshifters the scanning interval was actually fifty-six (twenty eightmultiplied by two).

Device 10 can also alter a definition of the multiple TDM time frames,active TDM lines and the like.

FIG. 2 illustrates portion 13 of device 10, according to an embodimentof the invention.

Portion 13 includes array 50 of line shifters 50-1-50-R, array of databuffers 90-1-90-R, data interface 182, multiple multiplexers 60,multiple multiplexer scanners 62, and controller 30 that includes alimit register 34, a write counter 32 and a data request unit 36. Inaddition a host TDM channel number register 172 and a host counter 174.

The host TDM channel number register 172 stores the number (Q) of theTDM channels that are expected to provide TDM channel data during atransmission session.

This number (Q) is provided to the channel counter 174 that sequentiallyscans the Q different channels during each scanning interval. Once Q TDMchannels were scanned the sequence restarts. The scanning depends uponthe TDM frames that should be transmitted over the K TDM lines.

The data request coming out of data request unit 36 is dependent on thestructure of the TDM frame. Channel counter 174 is used to indicate thechannel number required but the counter itself is dependent on the TDMframe.

The channel counter 174 is synchronized with various counters such asmultiplexer scanners 62 and data retrieval counter 32. Thus, while thechannel counter 174 repetitively scans a memory unit (such as memoryunit 11) that may store TDM channel data, the write counter 32 and thedata interface 182 scan the array of data buffers 90-1, and themultiplexer scanners 62 scan selected inputs of multiplexers 60.

The scanning interval of each of these scanners differ from eachother—the scanning interval of multiplexer scanner 62-k is n (as n lineshifters are allocated per one TDM line), the scanning interval of thedata retrieval counter 32 is R*j (as there are R active data buffers,and each data buffer can receive j data segments) while the scanninginterval of channel counter 174 is Q.

Limit register 34 stores a number S that equals R*j (S=R*J). Writecounter 32 is adapted to repetitively count from one to S, such as tosend data segments provided from host bus 102 to data interface 182 todifferent data buffers out of data buffers 90-1 till 90-R. If each databuffer can store two data segments then the first two data segments aresent to data buffer 90-1, the next two data segments are sent to databuffer 90-2 until the (2R−1)^(th) and the 2R^(th) data segments are sentto data buffer 90-R.

It is assumed that host bus 102 is data segment wide and that the databuffers are two data segment wide. Assuming that a data segment includesV bits then the data buffers and the line shifters are 2*V bit long. Thehost bus 102 is V+n bits wide, n being control bits, as well as thebuses between data retriever 40 to each data buffer, the bus betweeneach data buffer and each line shifter. The line shifters convert thereceived data segment to a serial stream of data.

It is noted that when the number of active TDM line changes (K changes)the number of active data buffers and number of active line shifters(the size of the array of line shifters and the array of the databuffers) can be changed accordingly.

For example, the inventors used a group of thirty-two line shifters. IfK equaled one, two, four, eight, sixteen or thirty-two than all thethirty-two data buffers and the thirty-two line shifters are active. IfK equals three, five or six then only thirty data buffers and thirtyline shifters are active. If K equals seven only twenty-eight buffersand twenty-eight line shifters are active.

Data request unit 36 can compare between the value stored within counter32 and limit register 34 and can also receive empty indications from theactive line shifters. According to a difference (if exists) between thevalue stored in write counter 32 and the value (R) stored in limitregister 34 and these empty indications the data request unit 36 cansend a request to receive new data. The request can be sent to the host.

FIG. 3 illustrates a line shifter 50-r and an empty detection unit 52-raccording to an embodiment of the invention.

Index r ranges between 1 and R.

Line shifter 50-r can receive (via parallel input 50,1-r) in parallel Vbits from corresponding data buffer 90-r. It then outputs these bits ina serial manner (via serial output 50,3-r) to a multiplexer 60-r once itis selected to provide said data to multiplexer 60-r.

The empty detection unit 52-r can be implemented in various mannersknown in the art. For example, it can include a counter that canindicate that line shifter 50-r is empty V cycles after it started tooutput data. It can also include a flag based mechanism. Such a flagbased mechanism is illustrated in U.S. Pat. No. 6,771,630 of Weits elal. A flag based mechanism is based upon an insertion of a predefinedsequence of bits during the serial output of data bits from the lineshifter.

For example, assuming that the line shifter has (V+1) bits, the datasegment is V bits long, and the line shifter is emptied from right toleft. Data is written to the second till (V+1)^(Th) bits of line shifterand “1” is written (via serial input 50,5-r) to the first bit (LeastSignificant Bit) of line shifter 50-r. During each of the next V clockcycles the data is shifted to the left and a sequence of “0” bits is fedto the LSB. Thus, after V clock cycles line shifter 50-r will stores astring that will include “1” followed by V “0” bits. Once this sequenceis detected (for example by monitoring the content of line shifter 50-rvia parallel output 50,4-r) empty detection unit 52-r indicates thatline shifter 50-r is empty. Those of skill in the art will appreciatethat other bits can be inserted. For example, the detected sequence caninclude a single “0” bit followed by V “1” bits. Yet for another examplethe flag can include multiple bits.

A clock signal is fed via input 50,2-r of line shifter 50-r. The sameclock signal can be fed to various components of device 10.Conveniently, this clock signal (also referred to as system clocksignal) differs from the clock signal provided to the TDM line (alsoreferred to as Tx clock signal).

FIG. 4 illustrates data interleaver 14-k and its environment accordingto another embodiment of the invention.

Data interleaver 14-k and its environment are part of device 10. Datainterleaver 14-k performs data interleaving operations.

Data interleaver 14-k is connected to TDM transmitter 20-k, and includesfirst input interface 122-k, second input interface 124-k, interleavingmultiplexer 126-k, interleaving command memory unit 130-k, retrievalunit 140-k and a interleaving controller 150-k.

Retrieval unit 140-k, interleaving command memory unit 130-k andinterleave controller 150-k are connected to each other. Interleavecontroller 150-k is further connected to a control input of interleavingmultiplexer 126-k. Two inputs of the interleaving multiplexer 126-k areconnected to the first and second input interfaces 122-k and 124-k.

The first input interface 122-k can receive data from a data source suchas but not limited to multiplexer 60-k. The second input interface 124-kcan receive data from another data source. Conveniently, theinterleaving multiplexer 126-k can be connected between multiplexer 60-kand TDM transmitter 20-k. It is noted that this is not necessarily soand interleaving multiplexer 126-k can be connected to an input ofserial interface 16 of FIG. 6.

Interleaving multiplexer 126-k, interleaving controller 150-k, retrievalunit 140-k facilitates a selection of data from the first or secondinput interfaces 124-k and 126-k.

It is noted that TDM line 9-k can be associated with a circuit thatincludes interleaving multiplexer 126-k, interleaving controller 150-kand retrieval unit 140-k, but this is not necessarily so. Theinterleaving command memory unit 130-k can store interleaving commandsrelating to multiple selections between multiple data sources andinterleaving multiplexer 126-k can be replaced by a multiplexing circuitthat has multiple outputs as well as multiple inputs.

Interleaving command memory unit 130-k is adapted to store a twodimensional array of interleaving command information that includesmultiple interleaving command information rows. Each row includesinterleaving commands associated with multiple TDM time slots.

The inventors used a 32*32 bit interleaving command memory unit 130-kthat includes 32 rows, of 32-bit each, whereas each bit indicatedwhether to select a data received at first input interface 122-k or atsecond input interface 124-k. It is noted that multiple bits can beallocated per TDM channel and that the two dimensional array can be usedto control multiple multiplexing decisions simultaneously, especially ifmultiple bits are allocated per multiple multiplexing decisions.

Retrieval unit 140-k is adapted to retrieve interleaving commandinformation rows from the interleaving command memory unit 130-k. It isadapted to receive or generate an access address 148 that indicates thenumber of TDM channel that is the subject of the interleaving decision.Access address 148 includes row selection portion 148-1 and inter-rowoffset portion 148-2. Row selection portion 148-1 is sent tointerleaving command memory unit 130-k and used to retrieve aninterleaving command row while inter-row offset portion 148-2 is used toselect a bit within the interleaving command row.

According to an embodiment of the invention the interleaving command rowincludes thirty-two bits. The value and location of bits within the rowindicates whether data associated with a certain TDM channel should beprovided from the first input interface 122-k or from the second inputinterface.

For example, if within the first row (value of the row selection portionis zero) the fifth, tenth and eighteen bits are set then data associatedwith the fifth tenth and eighteenth TDM channels will be provided fromthe second input interface 126-k.

Conveniently, the interleaving controller 150-k includes a decoder 152-kand a comparator 154-k that performs a bit-wise AND operation. Thedecoder 152-k decodes the inter-row offset from a (normal) binary formatto the format of the interleaving command row.

TABLE 1 illustrates various examples of exemplary interleaving commandinformation rows, inter-row offsets, decoded inter-row offsets and theresult of various comparisons between these values.

For simplicity of explanation only the two least significant bytes ofthese 32-bit long variables are shown. A “match” indicates that two “1”bits were found at the same location in both the interleaving commandrow and in the decoded inter-row offset.

TABLE 1 Interleaving Decoded inter- Comparison command row Inter-rowoffset row offset result 0000000001000001 00000000000001110000000001000000 Match (7^(th) bit) 0000000001000001 00000000000000010000000000000001 Match (1^(st) bit) 0000000001000001 00000000000010000000000010000000 No-match 0000000000001111 00000000000001000000000000001000 Match (4^(th) bit) 0000000000001111 00000000000000110000000000000100 Match (3^(rd) bit) 0000000000001111 00000000000000010000000000000001 Match (1^(st) bit) 0000000000001111 00000000000100001000000000000000 No-match

The first three interleaving command rows indicate that data associatedwith the first and seventh TDM channels should be provided from seconddata interface 124-k. The fourth till seventh interleaving command rowsindicate that data associated with the first till fourth TDM channelsshould be provided from second data interface 124-k. If a match occursthe data should be provided from second data interface 124.

Comparator 154-k conveniently includes multiple AND logic gates (an ANDgate is allocated for each bit of the interleaving command row) eachproviding an intermediate result, wherein are the AND logic gates areconnected to a single OR gate such as to provide a match result. Whenusing a thirty-two bit row there are thirty-two AND gates and a singleOR gate.

Conveniently, retrieval address 148 used by the retrieval unit 140-krepresents the TDM channel number that is being transmitted (or going tobe transmitted) during a current TDM time slot.

Conveniently, the first and second input interfaces 122-k and 124-k areadapted to enter a high impedance state when the other input interfaceis selected. According to another embodiment of the invention device 10includes additional circuitries that manage the interleaving process ofother data sources that can be associated with different TDM lines. Ifthere are K TDM lines there can be up to K different circuitries.

FIG. 4 also illustrates another data interleaver 14-j according to anembodiment of the invention.

Data interleaver 14-j (index j differs from index k) is connected toanother TDM transmitter 20-j and includes second interleaving commandmemory unit 130′, second retrieval unit 140′ and second interleavingcontroller 150′. These components are equivalent to TDM transmitter20-k, interleaving command memory unit 130-k, retrieval unit 140-k andinterleaving controller 150-k.

FIG. 5 illustrates data de-interleaver 14″-k according to an embodimentof the invention.

Data de-interleaver 14″-k performs de-interleaving while datainterleaver 14-k performs interleaving.

Device 10 includes data de-interleaver 14″-k that includes: receiver21-k that is adapted to receive data. Device 10 further includes: (i)first and second output interfaces 122″-k and 124″-k that are adapted toprovide information to a first data target and to a second data target,(ii) de-interleaving command memory unit 130″-k adapted to store a twodimensional array of de-interleaving command information that includesmultiple de-interleaving command information rows, each row includesde-interleaving commands associated with multiple TDM time slots; (iii)retrieval unit 140″-k adapted to retrieve de-interleaving commandinformation from the de-interleaving command memory unit; andde-interleaving controller 150″-k adapted to determine, in response tothe retrieved de-interleaving command information, whether to providedata to the first data target or to the second data target. Thedetermination affects de-multiplexer 126″-k that selectively provideddata to one out of interfaces 124″ and 126″.

Conveniently, retrieval unit 140″-k is adapted to retrievede-interleaving command information rows from the de-interleavingcommand memory unit 130″.

Conveniently, retrieval unit 140″ is adapted to access de-interleavingcommand memory unit 130″ by a retrieval address that comprises a rowselection portion and an inter-row offset portion.

FIG. 6 illustrates serial interface 16 according to another embodimentof the invention.

Serial interface 16 is designed in a modular manner and can be easilyadapted to serve additional data sources by either allowing an existingcontroller to control the transmission from another data source or byadding a new controller that can manage data sources that belong to newclock domains.

These data sources can include a data interleaver such as datainterleavers 14-k, 14-j, communication controller 13 and the like.

Serial interface 16 can output data via multiple outputs to multiplelines. It can multiplex data of various types over one or more outputsand the like.

Serial interface 16 includes transmission schedule memory unit 210,first intermediate storage unit 220, second intermediate storage unit230, transmission storage unit 240, multiplexer 250 and controllers260-280.

The output of serial interface 16 is the output of transmission storageunit 240. It can be connected to a physical layer unit 881 that in turnis connected to first communication channel 901 of FIG. 7. As serialinterface 16 aggregates data from many communication controllers overone or more lines the latter line can be referred to as a TDM line,although this line actually aggregates data aimed to multiple TDM lines.

An output of multiplexer 250 is to the input of transmission storageunit 240, while two inputs of multiplexer 250 are connected to first andsecond intermediate storage units 220 and 230 respectively. Transmissionstorage unit 240 is clocked by a transmission clock signal CLKTX thathas a transmission frequency Ftx.

Multiplexer 250 is controlled by timing controller 280 that determineswhich intermediate storage unit will provide data via multiplexer 250 totransmission storage unit 240.

First controller 260 is connected between a first group of data sources(collectively denoted 17) to first intermediate storage unit 220. Thesedata sources share the same clock signal—first clock signal CLK1 thathas a first frequency F1.

Second controller 270 is connected between a second group of datasources (collectively denoted 18) to second intermediate storage unit230. These data sources share the same clock signal—second clock signalCLK2 that has a second frequency F2.

F1 and F2 are higher than Ftx. Conveniently, F1 and F2 are higher thanat least 2*Ftx. The inventors used a 4:1 ratio between F1 and F2 andbetween Ftx. This clock frequency difference allows device 10 topre-fetch data to an intermediate data storage unit after it is emptiedand to stabilized this pre-fetched data before the next transmissioncycle. Communication controller 19 can be connected to first physicallayer unit 881.

Conveniently, the first clock frequency differs from the second clockfrequency. Conveniently, the stabilization period is responsive to holdand setup times of the intermediate storage units.

The frequency mismatch guarantees that the transmission section(including at least transmission storage unit 240) can sample data fromthe intermediate storage units without performing tedioussynchronization efforts.

Controller 280 receives CLK1, CLK2 and CLKTX and times the samplingoperations as well as the pre-fetch operations. As indicated above acontroller (such as controllers 260 and 270) is allocated per timedomain. Accordingly, multiple data sources can be added or removedwithout substantially altering the design of portion 16.

Conveniently, storage units 220, 230 and 240 are one-bit long, thuseliminating the need to provide complex pipeline control mechanisms.

The provision of data to transmission storage unit 240 as well as thepre-fetching of data to the first and second intermediate storage units220 and 230 is responsive to information representative of atransmission schedule of a TDM data frame stored within transmissionschedule memory unit 210.

Conveniently, controllers 260-280 cooperate in order to perform thefollowing tasks: (i) control a pre-fetch of a data segment to firstintermediate storage unit 220 from a data source out of a first group ofdata sources in response to a fullness level of first intermediatestorage unit 220 and in response to the transmission schedule; (ii)control a pre-fetch of a data segment to second intermediate storageunit 230 from a data source out of a second group of data sources inresponse to a fullness level of second intermediate storage unit 230 andin response to the transmission schedule, and (iii) control a provisionof a stabilized data segment from the first or the second intermediatestorage units 220 and 230 to the transmission storage unit 240, inresponse to the transmission schedule.

The following example illustrates some pre-fetch and data provisions. Itis assumed that F1 equals F2 and that F1=4*Ftx. It is also assumed thatthere is a one first clock cycle difference between CK1 and CLKTX.

It is assumed that the transmission schedule includes the followingsequence: two bits from data source 17-1, three bits from data source18-4, a bit from data source 18-1 and two bits from data source 17-2.Data sources 17-1 and 17-2 belong to first group of data sources 17.Data sources 18-1 and 18-4 belong to second group of data sources 18.

TABLE 2 illustrates a sequence of pre-fetch operations and provision ofdata to transmission storage unit 240.

TABLE 2 Clock cycle Operation First clock cycle Pre-fetching a firstdata bit from of CK1 and CK2 data source 17-1 to first intermediatestorage unit 220 and pre-fetching a first data bit from data source 18-4to second intermediate storage unit 230 Second clock cycle Providing thefirst data bit from of CLK1 (during 17-1 to transmission storage unitfirst clock cycle 240. of CLKTX) Third clock cycle Pre-fetching a seconddata bit of CK1 from data source 17-1 to first intermediate storage unit220 Fifth clock cycle Providing the second data bit from of CLK1 (during17-1 to transmission storage unit second clock cycle 240. of CLKTX)Sixth clock cycle Pre-fetching a first data bit from of CLK1 data source17-2 to first intermediate storage unit 220 Eighth clock cycle Providingthe first data bit from of CLK2 (during 18-4 to transmission storageunit third clock cycle 240. of CLKTX) Tenth clock cycle Pre-fetching asecond data bit of CLK2 from data source 18-4 to second intermediatestorage unit 230 Thirteenth clock Providing the second data bit fromcycle of CLK2 18-4 to transmission storage unit (during fourth 240.clock cycle of CLKTX) Fourteenth clock Pre-fetching a third data bitfrom cycle of CLK2 data source 18-4 to second intermediate storage unit230 Seventeenth clock Providing the third data bit from cycle of CLK218-4 to transmission storage unit (during fifth 240. clock cycle ofCLKTX) Eighteenth clock Pre-fetching a first data bit from cycle of CLK2data source 18-1 to second intermediate storage unit 230 Twenty firstclock Providing the first data bit from cycle of CLK2 18-1 totransmission storage unit (during sixth 240. clock cycle of CLKTX)Twenty second Pre-fetching a new data bit from clock cycle of CK2 datasource 18-4 to second intermediate storage unit 230 (for the nextiteration of the transmission sequence) Twenty fifth clock Providing thefirst data bit from cycle of CLK1 17-2 to transmission storage unit(during seventh 240. clock cycle of CLKTX) Twenty sixth clockPre-fetching a second data bit cycle of CLK1 from data source 17-2 tofirst intermediate storage unit 220 Twenty ninth clock Providing thesecond data bit from cycle of CLK1 17-2 to transmission storage unit(during eighth 240. clock cycle of CLKTX) Twenty sixth clockPre-fetching a new data bit from cycle of CLK1 data source 17-4 to firstintermediate storage unit 220 (for the next iteration of thetransmission sequence)

FIG. 7 illustrates device 10 according to an embodiment of theinvention.

Device 10 includes a general-purpose processor 812, a security engine814, system interface unit 818, communication engine 800 and multipleports (not shown). Components 812, 814, 818 and 800 are connected toeach other by local bus 816.

The general-purpose processor 812 can include multiple execution unitssuch as but not limited to an integer unit, a branch-processing unit, afloating-point unit, a load/store unit and a system register unit. Itcan also include various cache memories, dynamic power management unit,translation look aside buffers, and the like.

The general-purpose processor 812 controls device 10 and can executevarious programs according to the required functionality of device 10.The general-purpose processor 812 can be a member of the PowerPC™ familybut this is not necessarily so.

The security engine 814 can apply various security mechanisms includingencryption based mechanisms and the like.

Device 10 can be connected to multiple memory units as well as othercomponents. System interface unit 818 interfaces these components.System interface unit 818 may include some of the following components:external memory controllers, external DDR interface unit, PCI bridge,local bus, bus arbitrator, dual UART unit, dual I²C unit, a four channelDMA controller, an interrupt controller, and the like. It is noted thatother interfacing components can be used.

Communication engine 800 is a versatile communication component that canmanage multiple communication ports that operate according to differentcommunication protocols.

According to an embodiment of the invention multiple hardware Buffersshare the same first memory unit. This first memory unit usually storesat least one virtual Buffer per hardware Buffer.

Communication engine 800 includes multiple communication controllers ofdifferent types. Each communication controller can manage one or morecommunication channels. Conveniently, each communication channel isassociated with a single virtual buffer. A bi-directional communicationchannel is viewed as a combination of a receive communication channeland a transmit communication channel. Each such communication channelcan have its own information transfer controller, virtual buffers,hardware Buffer, and the like.

It is noted that one or more communication channels can be controlled bya single information transfer controller, but this is not necessarilyso.

The communication engine 800 includes two RISC processors 822 and 824,second level DMA controller 826, a shared data RAM memory unit 830, ashared instruction RAM memory unit 832, scheduler 834, two first levelDMA controllers 836 and 836, a second memory unit 840, eight universalcommunication controllers denoted UCC1-UCC8 842-856, one multi-channelcommunication controller 19, two serial communication controllers SP1860 and SP2 862, two serial interfaces 16 and 16′. It is noted thatadditional components, such as but not limited to various ports, timeslots assigners and the like were omitted for simplicity of explanation.

The first RISC processor 822 is connected to UCC1 842, UCC3 846, UCC5850, UCC7 857, MCC 19 190, SPI1 860, scheduler 834, shared instructionRAM memory unit 832 and shared data RAM memory unit 830. Scheduler 834can manage the access to first RISC processor 822.

The second RISC processor 824 is connected to UCC2 844, UCC4 848, UCC6852, UCC8 856, SPI2 862, scheduler 834, shared instruction RAM memoryunit 832 and shared data RAM memory unit 830. Scheduler 834 can managethe access to second RISC processor 824.

First level DMA controllers 836 and 838 are connected to the shared dataRAM memory unit 830 and to information transfer controllers (not shown)within the various communication controllers.

Each communication controller out of communication controllers UCC1-UCC8842-856, MCC 19, and SPI1-SPI2 860-862 can include transmission paths aswell as reception paths.

Conveniently, a UCC can support the following communication protocolsand interfaces (not all simultaneously): 10/100 Mbps Ethernet, 1000 MpbsEthernet, IPv4 and IPv6, L2 Ethernet switching using, ATM protocol viaUTOPIA interface, various types of HDLC, UART, and BISYNC.

Conveniently, MCC 19 supports two hundred and fifty six HDLC ortransparent channels, one hundred and twenty eight SS#7 channels ormultiple channels that can be multiplexed to one or more TDM interfaces.

In addition, communication engine 800 can include a controller (notshown) as well as an interrupt unit that coordinate the variouscomponents of the communication engine, as well as to enable thecommunication engine 800 to communicate with general-purpose processor812, security engine 814 and system interface unit 818.

Conveniently, a group of communication controllers are connected to asingle first level DMA controller, but this is not necessarily so. Forexample, first level DMA controller 836 serves communication controllersUCC1, UCC3, UCC5, UCC7, MCC1 and SPI1, while first level DMA controller338 serves communication controllers UCC2, UCC4, UCC6, UCC8 and SPI2.

The information frame transmitters can include PHY layer transmittersincluded within first and second physical layer units 881 and 882, aswell as MAC layer transmitters. The MAC layer transmitters form a partof each universal communication controller out of UCC1-UCC8 842-856. Thefirst and second communication interfaces 16 and 16′ can also beregarded as part of the information frame transmitters.

FIG. 8 illustrates method 300 for transmitting data, according to anembodiment of the invention.

Method 300 starts by stage 310 of receiving or defining a number of TDMlines the form the group of TDM lines. The group of TDM lines includesactive TDM lines-TDM TDM lines that participate in a transmissionsequence. It is noted that there can be additional TDM lines that do notparticipate in the transmission sequence. These TDM lines are alsoreferred to as deactivated TDM lines. It is noted that the number (andoptionally the identity) of active TDM lines can be defined by a user.It usually corresponds to the connectivity of a device that executedmethod 300 and alternatively or additionally to an application or taskexecuted by that device.

It is noted that the number of active TDM lines can be altered from oneiteration of method 300 to another and that change in this number alsochanges various scanning stages of method 300.

Usually, stage 310 includes selecting the TDM lines that participateduring a certain transmission session. The selection can includeselecting a sub-set of the possible TDM lines or selecting all the TDMlines.

Conveniently, stage 310 is followed by stage 315 of defining a number ofline shifters that form the array of line shifters in response to thenumber of TDM lines. The line shifters that form the array are referredto active line-shifters while line shifters that are not part of thatarray are also referred to as deactivated line shifters. Typically, allactive TDM lines are associated with the same number of line shifters.

For example, assuming that there is a group of G line shifters and thereare K active TDM lines than each TDM line will be serviced by n lineshifters, and the size of the line shifter array will be R (R equalsn*K), wherein R is not bigger than G and while (n+1)*K is bigger than G.In a mathematical form: n*K≦G≦(n+1)*K.

This allocation simplifies the control scheme of method 300, as there isa simple residual free mapping between active TDM lines and thedifferent data paths that are used to provide data segments to these TDMlines.

Stage 315 is followed by stage 330 of scanning at least a first memoryunit to retrieve data segments associated with multiple TDM channels, inresponse to a definition of multiple TDM time frames, each TDM timeframe includes multiple time slots. The scanning is conveniently doneusing one or more counters. The definition is performed by defining thenumber of active channels to be spread over the active TDM links.

Conveniently, the scanning includes scanning a scanning interval that isresponsive to the number of TDM lines that belong to the group of TDMlines.

Stage 330 is followed by stages 336 and 340. Stage 336 includesrepeating the scanning in response to an emptiness level of the array ofline shifters. Thus, when line shifters are empty, and especially whenall line shifters are empty new data can be retrieved from the firstmemory unit. Conveniently, the memory unit is scanned by a counter andthe repetition includes resetting the counter. The request for new datamay also be dependent on the data buffers according the required systemclock ratio and quality of service. The request may be connected in sucha manner that as soon as there is room in the buffers a request isasserted.

Stage 340 includes sending the retrieved data segments to an array ofline shifters. Stage 340 can include sending sequences of retrieved datasegments to sequences of line shifters within the array of lineshifters. AN optional stage of generating a data request may follow thisstage.

Stage 340 is followed by stage 360 of multiplexing data segmentsprovided from the array of line shifters, in response to the definition,such as to provide in a parallel manner multiple data segments tomultiple TDM lines. For example, if K TDM lines are active then K datasegments can be sent in parallel from different line shifters.

Conveniently, stage 360 includes stage 362 of scanning selected inputsof multiple multiplexers. For example, assuming that: (i) there are Kmultiplexers that are connected to K active TDM lines, (ii) n lineshifters are allocated per TDM line, and (iii) each multiplexer is alsoconnected to the G line shifters. In this case a multiplexer that isconnected to a certain TDM line is controlled by sequentially scanning nmultiplexer inputs connected to n active line shifters associated withthat certain TDM line.

Stage 360 is followed by stage 380 of transmitting a group of TDM dataframes over a group of TDM lines. Each TDM line can be viewed asconveying a single TDM frame. Thus, by using multiple (K) TDM lines KTDM frames are sent in parallel to each other.

Stage 380 can be followed by jumping to stage 330 and alternatively oradditionally by stage 390 of altering a definition of the multiple TDMtime frames. This alteration may include changing the number (and/or theidentity) or active TDM lines, changing the time slots allocated for TDMchannels and the like.

According to an embodiment of the invention the transmitting can alsoinclude interleaving data provided from one or more multiplexers withdata provided from other data sources. This interleaving may involveapplying at least one of the stages of method 400 of FIG. 9.

According to yet another embodiment of the invention the transmittingcan also include sending data segments from data sources of differentclock domains to a unit that can then send selected data segments overthe TDM line. Accordingly the transmission can involve at least onestage of method 600 of FIG. 10.

An exemplary implementation of method 300 is illustrated in FIG. 1. Itis noted that other circuits can implement method 300 without departingfrom the spirit of the invention.

FIG. 9 illustrates method 400 for transmitting data, according to anembodiment of the invention.

Method 400 starts by stage 440 of retrieving interleaving commandinformation from a two dimensional array of interleaving commandinformation. The two dimensional array includes multiple interleavingcommand information rows. Each row includes interleaving commandsassociated with multiple TDM time slots.

Conveniently, stage 440 includes stage 444 of retrieving an interleavecommand information row.

Conveniently, stage 440 includes accessing a memory unit by a retrievaladdress that includes a row selection portion and an inter-row offsetportion.

Stage 440 is followed by stage 460 of determining, in response to theretrieved interleaving command information, whether to provide data froma first data source or from a second data source.

Conveniently, stage 460 of determining includes comparing between theinter-row offset portion and a retrieved interleave command informationrow.

Conveniently, stage 460 of determining includes performing a bit wisecomparison between the inter-row offset portion and a retrievedinterleave command information row to provide intermediate comparisonresults and applying a logical OR operation on the intermediatecomparison results to provide a comparison result.

Conveniently, stage 460 includes determining whether to provide datafrom a first data source or from a second data source in response to thevalue and to the location of interleave command bits within a retrievedinterleave command information row.

Conveniently, interleaving command information includes a bit per TDMchannel. This bit allows a selection between two different data sources.It is noted that 2^(R) bits can be used for selecting between Rdifferent data sources.

Stage 460 is followed by stage 480 of providing data over a timedivision multiplex (TDM) line.

Stage 460 can also be followed by stage 490 of altering a retrievaladdress used for retrieving interleaving command information and jumpingto the stage of retrieving, such as to scan the two-dimensional array.

Conveniently, method 400 includes instructing an interface coupled to anon-selected data source to enter a high impedance state.

According to an embodiment of the invention multiple two-dimensionalarray of interleaving command information are provided. Eachtwo-dimensional array can be used for selecting between two (or more)data sources. Each two-dimensional array can control the transmissionover a single TDM line.

Conveniently, method 400 can include the following additional optionalstages: stage 440′ of retrieving interleaving command information from asecond two dimensional array of interleaving command information; stage460′ of determining, in response to the retrieved interleaving commandinformation from the second two dimensional array, whether to providedata from a third data source or from a fourth data source over thesecond TDM line; and stage 480′ of providing data over another timedivision multiplex (TDM) line.

An exemplary implementation of method 400 is illustrated in FIG. 4. Itis noted that other circuits can implement method 400 without departingfrom the spirit of the invention.

FIG. 10 illustrates method 500 for de-interleaving data, according to anembodiment of the invention.

Method 500 starts by stage 520 of receiving data over a TDM line.

Stage 520 is followed by stage 540 of retrieving de-de-interleavingcommand information from a two dimensional array of de-interleavingcommand information. The two dimensional array includes multiplede-interleaving command information rows. Each row includesde-interleaving commands associated with multiple TDM time slots.

Conveniently, stage 540 includes stage 544 of retrieving ande-interleave command information row.

Conveniently, stage 540 includes accessing a memory unit by a retrievaladdress that includes a row selection portion and an inter-row offsetportion.

Stage 540 is followed by stage 560 of determining, in response to theretrieved de-interleaving command information, whether to provide datato a first data target or to a second data target.

Conveniently, stage 560 of determining includes comparing between theinter-row offset portion and a retrieved de-interleave commandinformation row.

Conveniently, stage 560 of determining includes performing a bit wisecomparison between the inter-row offset portion and a retrievedde-interleave command information row to provide intermediate comparisonresults and applying a logical OR operation on the intermediatecomparison results to provide a comparison result.

Conveniently, stage 560 includes determining whether to provide data toa first data source or to a second data source in response to the valueand to the location of de-interleave command bits within a retrievedde-interleave command information row.

Conveniently, de-interleaving command information includes a bit per TDMchannel. This bit allows a selection between two different data outputs.It is noted that 2^(R) bits can be used for selecting between Rdifferent data outputs.

Stage 560 can also be followed by stage 590 of altering a retrievaladdress used for retrieving de-interleaving command information andjumping to the stage of retrieving, such as to scan the two-dimensionalarray.

According to an embodiment of the invention multiple two-dimensionalarray of de-interleaving command information are provided. Eachtwo-dimensional array can be used for selecting between two (or more)data targets. Each two-dimensional array can control the reception ofdata from a single TDM line.

FIG. 11 illustrates a flow chart of method 600, according to anembodiment of the invention.

Method 600 starts by stage 610 of defining a transmission schedule of aTDM data frame that includes multiple TDM time slots allocated fortransmitting data over a TDM line.

Stage 610 is followed by stage 615 of providing a transmission clocksignal having a transmission clock frequency to the TDM line, providinga first clock signal having a first clock frequency to data sources thatbelong to a first group of data sources and providing a second clocksignal having a second clock frequency to data sources that belong to asecond group of data sources; the first clock frequency and the secondclock frequency are higher than the transmission clock frequency.

Stage 615 is followed by stage 620 and 630.

Stage 620 includes pre-fetching to a first intermediate storage a datasegment from a data source out of the first group of data sources inresponse to a fullness level of the first intermediate storage unit andto the transmission schedule.

Stage 630 includes pre-fetching to a second intermediate storage a datasegment from a data source out of the second group of data sources inresponse to a fullness level of the first intermediate storage unit andto the transmission schedule.

Stage 620 and 630 is followed stage 640 of providing in response to thetransmission schedule, a stabilized data segment from the first or thesecond intermediate storage units to a transmission storage unit.

Conveniently, the stage 640 of providing includes sampling the datasegment at the transmission clock frequency.

Stage 640 is followed by stage 650 of transmitting the data segment fromthe transmission storage unit over the TDM line.

An exemplary implementation of method 600 is illustrated in FIG. 6. Itis noted that the other circuits can implement method 600 withoutdeparting from the spirit of the invention.

Variations, modifications, and other implementations of what isdescribed herein will occur to those of ordinary skill in the artwithout departing from the spirit and the scope of the invention asclaimed. Accordingly, the invention is to be defined not by thepreceding illustrative description but instead by the spirit and scopeof the following claims.

1. A method for transmitting data, the method comprises: transmitting agroup of time division multiplexed data frames over a group of TDMlines; scanning at least a first memory unit to retrieve data segmentsassociated with multiple TDM channels, in response to a definition ofmultiple TDM time frames, each TDM time frame comprises multiple timeslots; sending the retrieved data segments to an array of line shifters;and multiplexing data segments provided from the array of line shifters,in response to the definition, such as to provide in a parallel mannermultiple data segments to multiple TDM lines.
 2. The method according toclaim 1 further comprising defining a number of TDM lines out of aplurality of TDM lines that are to be activated to form the group of TDMlines.
 3. The method according to claim 2 wherein a scanning intervalbeing scanned during the scanning is responsive to the number of TDMlines.
 4. The method according to claim 2 further comprising defining anumber of line shifters that form the array of line shifters in responseto the number of TDM lines.
 5. The method according to claim 4 whereinthe array of line shifters are selected from a group of multiple lineshifters wherein the array of line shifters comprises n*K line shifters,wherein K is a number of TDM lines, n is a positive integer, and whereinn*K is not bigger than G while (n+1)*K is bigger than G.
 6. The methodaccording t: claim 1 further comprising providing a first clock signalto the array of line shifters and to multiplexers that perform themultiplexing while providing at least one other clock signal tomultiple. TDM transmitters that perform the transmitting.
 7. The methodaccording to claim 1 wherein the multiplexing comprises scanningselected inputs of multiple multiplexers.
 8. The method according toclaim 1 further comprising: repeating the scanning in response to anemptiness level of the array of line shifters.
 9. The method accordingto claim 1 wherein the scanning at least a first memory unit and ascanning of selected inputs of multiple multiplexers comprise utilizingcounters that are synchronized to each other.
 10. The method accordingto claim 1 further comprising altering a definition of the multiple TDMtime frames.
 11. A device comprising: multiple time division multiplextransmitters to transmit a group of data frames over a group of TDMlines; a controller to define or receive a definition of multiple TDMtime frames, whereas each TDM time frame comprises multiple time slots;a data retriever to scan at least a first memory unit to retrieve datasegments associated with multiple TDM channels, in response to thedefinition and to send the retrieved data segments to an array of lineshifters; and multiple multiplexers to multiplex data segments providedfrom the array of line shifters, in response to the definition, such asto provide in a parallel manner multiple data segments to multiple TDMtransmitters.
 12. The device according to claim 11 wherein thecontroller to receive or define a number of TDM lines the form the groupof TDM lines.
 13. The device according to claim 12 wherein the dataretriever to scan the at least first memory unit at a scanning intervalthat is responsive to the number of TDM lines.
 14. The device accordingto claim 12 wherein the device to define a number of line shifters thatform the array of line shifters in response to the number of TDM lines.15. The device according to claim 14 wherein the device comprises agroup of line shifters, the array of line shifters is selected from thegroup of line shifters; the array of line shifters comprises n*K lineshifters, K is a number of TDM lines, n is a positive integer; andwherein n*K is not bigger than G while (n+1)*K is bigger than G.
 16. Thedevice according to claim 11 further comprising at least one clocksignal provider to provide a first clock signal to the array of lineshifters and to the multiple multiplexers and to provide at least oneother clock signal to the multiple TDM transmitters.
 17. The deviceaccording to claim 11 wherein the multiple multiplexers are coupled tomultiple multiplexer scanners to scan selected inputs of the multiplemultiplexers.
 18. The device according to claim 11 wherein the device torepeat scanning the at least first memory unit in response to anemptiness level of the array of line shifters.
 19. The device accordingto claim 11 further comprising a data retrieval counter that issynchronized to multiple multiplexer scanners.
 20. The method of claim 1wherein the definition of multiple TDM time frames is performed bydefining a number of active channels to be spread over the group of TDMlines.